uart/avrdude/README: updated build instructions and added OpenWRT

- README: removed unnecessary "make" run after second "configure"
- README: added brief explanation why we need to run "configure" twice
- README: added build instructions for OpenWRT

uart/avrdude/README

@@ -1,3 +1,5 @@
+# --- build instructions common for OpenWRT and Jlime -------------------------
+
 wget http://download.savannah.gnu.org/releases/avrdude/avrdude-5.10.tar.gz
 tar xfz avrdude-5.10.tar.gz
 cd avrdude-5.10
@@ -6,11 +8,23 @@ quilt push -a
 
 aclocal
 automake
+
+# --- build instructions for OpenWRT ------------------------------------------
+
+./configure --prefix=/ --host=mipsel-openwrt-linux
+make
+# the joy of autocrap (we need this to generate avrdude.conf)
+./configure --prefix=/ --host=mipsel-openwrt-linux
+
+scp avrdude.conf ben:/etc/
+scp avrdude ben:/usr/bin/
+
+# --- build instructions for Jlime --------------------------------------------
+
 ./configure --prefix=/ --host=mipsel-linux
 make </dev/null
-# the joy of autocrap
+# the joy of autocrap (we need this to generate avrdude.conf)
 ./configure --prefix=/ --host=mipsel-linux
-make
 
 scp avrdude.conf jlime:/etc/
 scp avrdude jlime:/usr/bin/